Excel Guru, please help!

I try to create a code when user save the workbook, the file name will
be taken from cell C10 & C7. It works fine with save button, but if I
select File-Save as, the code will run twice, if I disable the
enableevents it will disactivate another code in other sheets. Thanks

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As
Boolean)

filesavename = Application.GetSaveAsFilename(Sheet1.Range("C10") &
Sheet1.Range("C7"), fileFilter:="Microsoft Excel Workbook (*.xls),
*.xls")

If filesavename < False Then

Else
Cancel = True
End If
end sub